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Open-ended questions in web-survey/Interview
Item #
0401 #1
Contextual features and
Common incorrect model
MassObject with larger mass
exerts a larger force
Student responses in interview/web-survey
“Force is calculated my multiplying mass by acceleration. If both the truck and the car are traveling at the same
acceleration than the only way for the force to not be equal is find which has the larger mass.”
“Since a=F/m, and they are traveling at the same speed, the mass is the only independent variable. Since the truck
has much more mass, it exerts a much larger force on the car than the car on the truck.”.
“Because force=mass*acceleration, and acceleration for both vehicles is equal, the car with more mass will do more
damage.”
“The truck is more massive and F=MA says that the truck will exert more force on the car than vice-versa.”
“The truck has a larger mass than the car, so the truck is going to exert a larger force on the car than the car will on
the truck when they collide. Then by using Newton's law "Objects in motion tend to stay in motion", the truck with
the larger mass will want to stay in motion more than the car, so the truck will push the car backwards.”
“I agree with the student’s reasoning based on Newton’s second law. The truck’s force will be greater than the car’s
simply because it has more mass than the car and they are traveling the same velocity.”
“I recite the equation F = ma. First, if an object has a mass and acceleration, a force will be produced. Since the cars
will be colliding, they with both slow considerably, so they will have acceleration. Second, since the truck has a
much larger mass, it will produce a much larger force.”
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Item #
0401 #2
Contextual features and
Common incorrect model
Student responses in interview/web-survey
VelocityObject with larger velocity
exerts a larger force
“Max's marble had a greater force on it from the beginning thus giving it a higher velocity and momentum than
Jimmy's marble. So when they hit, Max's marble does exert a greater force on Jimmy's.”
“The marble with the larger velocity will exert the larger force, and that is Max's marble. Then once again using
Newton’s law "Objects in motion tend to stay in motion", Max's marble, with the higher velocity, will want to stay
in motion more, so it could push Jimmy's marble backwards.”
“The student is correct. If two identical marbles are thrown at each other, one with a greater initial velocity, the
faster marble will exert a greater force on the other.”
“F = ma. I agree with the above statement. The force exerted by Max’s marble is greater than the force exerted by
Jimmy’s marble because it is moving faster.”
[in the following cases, faster means larger acceleration]
“I think that his reasoning concerning the evidence is logical. When you look at the force=mass x acceleration you
notice that the masses of the two objects are the same and the acceleration of Max's marble is going to be more then
Jimmy's Marble.”
“Since they are of the same mass, but one has a larger speed, it will have a larger acceleration when the two collide,
and the larger force produced by the faster marble will have probably force jimmy's marble to move backward.”
“I agree because since they are of the same mass, but one has a larger speed, it will have a larger acceleration when
the two collide, and the larger force produced by the faster marble will have probably force jimmy’s marble to
move backward.”
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Item #
Contextual features and
Common incorrect model
Student responses in interview/web-survey
0401 #2
ThrowingObject thrown by stronger
person exert larger force
“If Max is stronger then his marble will have a greater acceleration. This means that Max's marble will have a
greater force pushing on Jimmy's marble than Jimmy's marble will have pushing on Max's marble
“Since max threw it harder, it would have a larger force, and therefore since and the masses are the same, then the
acceleration of Max's marble is greater and will push jimmy's back.”
“Since the problem stated that they have equal mass but Max is stronger and his is moving faster, it can be
determined that his will have a greater force on the other marble then Jimmy's marble will have on Max's.”
“Max's marble travels faster because he is stronger, it has a bigger acceleration. So it would exert more force.”
0401 #3
PushingObject that “pushing” exerts
a large force
“Both Amy and Jane exert a force on each other but depending on how Amy pushes, her force could possibly be
greater. Both have the same mass but the acceleration is not mention to determine the force, that is why Jane may
move faster.”
“There would be forces exerted on both people. But depending on how the person was pushed, Amy could be
exerting a larger force than Jane.”
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